[fp-enhancer] Improve pkg/cli: replace bubble sort, use sliceutil.Map, migrate to slices package

[github-actions]

Functional and immutability improvements to the pkg/cli package. This is run 1 of a systematic round-robin series covering all packages.

Next package to process: pkg/console

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Summary

Three files updated with tasteful functional improvements:

File	Change	Impact
health_command.go	Bubble sort → slices.SortFunc	O(n²)→O(n log n), 8 lines → 3 lines
compile_config.go	Nested loops → sliceutil.Map + pure helper	Declarative, composable
logs_report.go	9× sort.Slice/sort.Strings → slices.SortFunc/slices.Sort	Type-safe, index-free, removes sort import

Net: 38 insertions, 53 deletions (net −15 lines)

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1. Replace Bubble Sort with slices.SortFunc (health_command.go)

Before — O(n²) bubble sort with a comment apologizing for it:

// Sort by success rate (lowest first to highlight issues)
// Using a simple bubble sort for simplicity
for i := 0; i < len(workflowHealths); i++ {
    for j := i + 1; j < len(workflowHealths); j++ {
        if workflowHealths[i].SuccessRate > workflowHealths[j].SuccessRate {
            workflowHealths[i], workflowHealths[j] = workflowHealths[j], workflowHealths[i]
        }
    }
}

After — O(n log n), expressive, uses the standard slices package:

// Sort by success rate ascending (lowest first to highlight issues)
slices.SortFunc(workflowHealths, func(a, b WorkflowHealth) int {
    return cmp.Compare(a.SuccessRate, b.SuccessRate)
})

2. Declarative Sanitization with sliceutil.Map (compile_config.go)

Before — nested imperative loops with index tracking:

sanitized := make([]ValidationResult, len(results))
for i, result := range results {
    sanitized[i] = ValidationResult{
        ...
        Errors:   make([]CompileValidationError, len(result.Errors)),
        Warnings: make([]CompileValidationError, len(result.Warnings)),
    }
    for j, err := range result.Errors {
        sanitized[i].Errors[j] = CompileValidationError{...}
    }
    for j, warn := range result.Warnings {
        sanitized[i].Warnings[j] = CompileValidationError{...}
    }
}
return sanitized

After — extracted pure helper + declarative nested Map:

sanitizeError := func(e CompileValidationError) CompileValidationError {
    return CompileValidationError{
        Type:    e.Type,
        Message: stringutil.SanitizeErrorMessage(e.Message),
        Line:    e.Line,
    }
}

return sliceutil.Map(results, func(result ValidationResult) ValidationResult {
    return ValidationResult{
        Workflow:     result.Workflow,
        Valid:        result.Valid,
        CompiledFile: result.CompiledFile,
        Errors:       sliceutil.Map(result.Errors, sanitizeError),
        Warnings:     sliceutil.Map(result.Warnings, sanitizeError),
    }
})

3. Type-safe Sorting with slices.SortFunc (logs_report.go)

Replaced 6 sort.Slice + 3 sort.Strings calls with their type-safe equivalents from the slices package. The sort package import is removed entirely.

Benefits:

• Comparison functions receive typed values (a, b T) instead of index-based result[i]/result[j]
• cmp.Compare eliminates hand-written comparison logic
• slices.Sort replaces sort.Strings consistently
• Aligns with existing use of slices.Contains already in the file

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Principles Applied

1. Pure function extraction: sanitizeError is a pure function — same input always gives same output, no side effects, easily testable in isolation
2. Declarative over imperative: sliceutil.Map expresses what to transform, not how to iterate
3. Standard library preference: slices package (Go 1.21+) over sort package for type-safe slice operations
4. No behavioral changes: All transformations are functionally equivalent

Testing

• ✅ TestHealthConfigValidation, TestHealthCommand, TestCalculateWorkflowHealth, TestGroupRunsByWorkflow, TestCalculateHealthSummary — all pass
• ✅ TestBuildMCPToolUsageSummarySorting — passes (validates sort order maintained)
• ✅ go build ./pkg/cli/ — clean
• ✅ go vet ./pkg/cli/ — clean
• ✅ make fmt — no changes needed

Generated by Functional Pragmatist · ◷

• expires on Mar 11, 2026, 9:31 AM UTC

[Copilot]

Pull request overview

This PR modernizes pkg/cli by replacing index-based sorting and imperative slice transformations with Go’s slices/cmp helpers and a small functional mapping utility, improving readability and reducing algorithmic complexity where applicable.

Changes:

• Replaced a manual bubble sort with slices.SortFunc + cmp.Compare in health summary sorting.
• Refactored validation result sanitization to a pure helper + nested sliceutil.Map transforms.
• Migrated multiple sort.Slice/sort.Strings usages to slices.SortFunc/slices.Sort, removing the sort import.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
pkg/cli/health_command.go	Replaces bubble sort with slices.SortFunc for success-rate ordering.
pkg/cli/compile_config.go	Uses sliceutil.Map and a pure sanitizer helper to produce sanitized validation output.
pkg/cli/logs_report.go	Replaces index-based sorting with type-safe slices sorting and cmp.Compare.

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